S.M. Mann

Publications of S.M. Mann

• Public exposure to radio waves near GSM microcell and picocell base stations.

  Authors: T G Cooper, S M Mann, M Khalid, R P Blackwell

  Journal of radiological protection : official journal of the Society for Radiological Protection. 07/2006; 26(2):199-211.

  Exposures of the general public to radio waves at locations near 20 randomly selected GSM microcell and picocell base stations in the UK have been assessed in the context of the InternationalExposures of the general public to radio waves at locations near 20 randomly selected GSM microcell and picocell base stations in the UK have been assessed in the context of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. Compliance distances were calculated for the antennas of the base stations from their reported radiated powers. Under pessimistic assumptions that would maximise exposures, the minimum height at which the general public reference level could potentially be exceeded near any of the base station antennas was calculated to be 2.4 m above ground level. The power densities of the broadcast carriers transmitted by the base stations have been measured and scaled to include all other possible carriers. Exposures were generally in the range 0.002-2% of the ICNIRP general public reference level, and the greatest exposure quotient near any of the base stations was 8.6%. Exposures close to microcell base stations were found to be generally greater than those close to macrocell base stations.

• Assessment of occupational exposure to radiofrequency fields and radiation.

  Authors: T G Cooper, S G Allen, R P Blackwell, I Litchfield, S M Mann, J M Pope, M J A van Tongeren

  Radiation protection dosimetry. 02/2004; 111(2):191-203.

  The use of personal monitors for the assessment of exposure to radiofrequency fields and radiation in potential future epidemiological studies of occupationally exposed populations has beenThe use of personal monitors for the assessment of exposure to radiofrequency fields and radiation in potential future epidemiological studies of occupationally exposed populations has been investigated. Data loggers have been developed for use with a commercially available personal monitor and these allowed personal exposure records consisting of time-tagged measurements of electric and magnetic field strength to be accrued over extended periods of the working day. The instrumentation was worn by workers carrying out tasks representative of some of their typical daily activities at a variety of radio sites. The results indicated significant differences in the exposures of workers in various RF environments. A number of measures of exposure have been examined with a view to assessing possible exposure metrics for epidemiological studies. There was generally a good correlation between a given measure of electric field strength and the same measure of magnetic field strength.

• UK and European guidelines on protection from radiofrequency radiation

  Authors: S.M. Mann

  Electromagnetic Assessment and Antenna Design Relating To Health Implications of Mobile Phones (Ref. No. 1999/043), IEE Seminar on; 02/1999

  The UK Government is concerned about the level of interest in mobile phones and the Health Minister has asked the NRPB to set up an independent Expert Group to look specifically at the health issue.The UK Government is concerned about the level of interest in mobile phones and the Health Minister has asked the NRPB to set up an independent Expert Group to look specifically at the health issue. The NRPB is the organisation to which Government, industry and the public turn for independent scientific advice on protection from radiation hazards. The paper reviews the protection guidelines published by independent scientific bodies such as NRPB and ICNIRP and comment upon the compliance of mobile telephone handsets

• Characteristics of the skeletal biconical antenna as used for EMC applications

  Authors: S.M. Mann, A.C. Marvin

  Electromagnetic Compatibility, IEEE Transactions on. 12/1994;

  The Numerical Electromagnetics Code (NEC) is used to simulate the radiators of a skeletal biconical antenna and the model is optimized to return a drive point impedance as close as possible toThe Numerical Electromagnetics Code (NEC) is used to simulate the radiators of a skeletal biconical antenna and the model is optimized to return a drive point impedance as close as possible to measured values. The horizontally polarized model is then illuminated in free space and above a ground plane to deduce its plane-wave antenna factors and their variations as functions of height. It is shown that changes in effective length have to be considered in addition to changes in impedance mismatch when calculating antenna factor variations with the biconical antenna, although only the latter are necessary with a resonant dipole. The measured scattering parameters of the balun of the biconical antenna are then incorporated with the NEC simulation to give a complete model of the real antenna

• SAR calculations in an anatomically realistic model of the head for mobile communication transceivers at 900 MHz and 1.8 GHz.

  Authors: P J Dimbylow, S M Mann

  Physics in medicine and biology. 11/1994; 39(10):1537-53.

  A new mathematical model of the head has been constructed from a set of serial MRI slices from one subject. Finite-difference time-domain (FDTD) calculations of the specific energy absorption rateA new mathematical model of the head has been constructed from a set of serial MRI slices from one subject. Finite-difference time-domain (FDTD) calculations of the specific energy absorption rate (SAR) have been performed on this model with a 2 mm resolution for a generic mobile communication transceiver represented by a quarter-wavelength monopole on a metal box. The antenna was mounted either at the centre or corner of the top face of the box. The frequencies considered were 900 MHz and 1.8 GHz. Three irradiation geometries were considered, a vertical handset in front of the eye and vertical and horizontal orientations at the side of the ear. The effect of a hand grasping the handset was considered. The head model was scaled to represent the head of an infant and a subset of calculations was performed to verify that the SAR deposited in the infant head did not exceed that in the adult. Results are also presented for a half-wavelength dipole. The maximum SAR values produced by the generic transceiver for the horizontal orientation at the side of the head which is the most typical position, averaged over 10 g of tissue at 900 MHz and 1.8 GHz, are 2.1 and 3.0 W kg(-1) per W of radiated power. The corresponding values over 1 g of tissue are 2.3 and 4.8 W kg(-1) per W at 900 MHz and 1.8 GHz. However, if one were to consider all possible operational conditions, the placement of the transceiver in front of the eye will give 3.1 and 4.6 W kg(-1) per W averaged over 10 g of tissue and 4.7 and 7.7 W kg(-1) per W over 1 g of tissue at 900 MHz and 1.8 GHz, respectively.

• Experimental study of the calibration of antenna-screened enclosure combinations for radiated emission measurements in the frequency range from 1 to 30 MHz

  Authors: A.C. Marvin, S.M. Mann

  Science, Measurement and Technology, IEE Proceedings -. 08/1994;

  An experimental study of the calibration of antenna-screened enclosure combinations is described in the frequency range 1-30 MHz. It is shown that such a combination can be used, in conjunction withAn experimental study of the calibration of antenna-screened enclosure combinations is described in the frequency range 1-30 MHz. It is shown that such a combination can be used, in conjunction with a spherical dipole transfer standard, to provide estimates of the electric and magnetic fields that would be radiated by equipment on an open area test site from measurements performed on the equipment in a nonanechoic screened enclosure

• The development of an optimal NEC model of a skeletal biconicalantenna for use with antenna factor prediction

  Authors: S.M. Mann, A.C. Marvin

  Application and Validation of Design Tools for Antennas, IEE Colloquium on; 07/1993

  A useful development of the modelling approach to antenna calibration is to accept that it is not practical to measure antenna factors directly and instead compare values of another antennaA useful development of the modelling approach to antenna calibration is to accept that it is not practical to measure antenna factors directly and instead compare values of another antenna parameter, which can be measured accurately, with predictions derived from a model. One such parameter is drive-point impedance and, if a model can be developed which returns a drive-point impedance that agrees with measurement, the model may then be used with confidence to predict antenna factors. The paper shows how the drive-point impedance of a Schwarzbeck BBA9106 biconical antenna may be measured and then used as a guide to facilitate production of an accurate NEC model of the antenna. This model is then combined with the measured scattering parameters of the balun of the antenna in order to yield predicted antenna factors for the complete real antenna

• Some measurements of field uniformity within commonly used environments for radiated susceptibility measurements

  Authors: L. Dawson, S.M. Mann, A.C. Marvin

  Electromagnetic Compatibility, 1992., Eighth International Conference on; 10/1992

  Measurements of field strength are made in a 7×7×7 array of positions within a 50 cm cubic volume, in eleven environments that are commonly used for radiated susceptibility testing. TheMeasurements of field strength are made in a 7×7×7 array of positions within a 50 cm cubic volume, in eleven environments that are commonly used for radiated susceptibility testing. The average value, absolute variation and standard deviation of the fields are analysed to deduce the field uniformity levels in each environment for the frequency range of 30-230 MHz. A simulated item of equipment under test is also used to assess the suitability of each environment for making repeatable measurements. It is concluded that semi-anechoic chambers offer the best environment in which to perform susceptibility measurements, but that stripline cells used in small damped screened rooms can offer a similar level of repeatability. A criterion, that the standard deviation of the fields over the volume occupied by the equipment under test should be at least 13 dB down from the mean field, is proposed for a general environment to provide repeatable measurements

• A computer study of the calibration of the skeletal biconical antenna and the resonant dipole antenna

  Authors: S.M. Mann, A.C. Marvin

  Radiated Emission Test Facilities, IEE Colloquium on; 07/1992

  The plane-wave antenna factors of the resonant dipole antenna and the skeletal biconical antenna are derived from a computer simulation approach in order to obtain accurate values. The method forThe plane-wave antenna factors of the resonant dipole antenna and the skeletal biconical antenna are derived from a computer simulation approach in order to obtain accurate values. The method for calibration of the skeletal biconical antenna also shows how the effects of a balun may be incorporated into a theoretical antenna factor

• A statistical description of field uniformity and its effect on the measured immunity of equipment under test

  Authors: L. Dawson, S.M. Mann, A.C. Marvin

  Role of Statistics in EMC Specification Design and Clearance, IEE Colloquium on; 06/1992

  During radiated susceptibility measurements the equipment under test (EUT) is exposed to field strengths of up to several volts per metre. These high field levels cannot be radiated in unboundedDuring radiated susceptibility measurements the equipment under test (EUT) is exposed to field strengths of up to several volts per metre. These high field levels cannot be radiated in unbounded test environments, such as open-area test sites, and so a variety of screened room and absorber lined chamber environments are used instead. The screened rooms form resonant cavities and absorber material is not very efficient, in the frequency range from 30-200 MHz, so that the field that illuminates EUTs in these environments is far from uniform. The objective of the project was to measure the field uniformity within typical radiated susceptibility testing environments and to assess its effect on the repeatability of measurements performed within them

• Computer aided design for radio-frequency interference reduction

  Authors: A.C. Marvin, J.M. Tealby, T.J.F. Carr-Brion, S.J. Porter, S.M. Mann

  Electromagnetic Compatibility, 1990. Seventh International Conference on; 09/1990

  Describes the requirements for a computer aided design (CAD) package to predict radiated emissions from electronic equipment and to aid their reduction. Input for the package is obtained from a suiteDescribes the requirements for a computer aided design (CAD) package to predict radiated emissions from electronic equipment and to aid their reduction. Input for the package is obtained from a suite of CAD tools covering electrical and mechanical aspects of electronic equipment design. An electromagnetic solver using a method of moments technique is described and its current performance is indicated. The methods and problems of interfacing the package with the existing CAD packages are described, as are some of the challenges facing future users of integrated packages of this type

• A CAD package for the prediction and reduction of radio-frequencyinterference from microprocessor based electronic equipment

  Authors: A.C. Marvin, J.M. Tealby, T.J.F. Carr-Brion, S.J. Porter, S.M. Mann

  Interference and Design for EMC in Microprocessor Based Systems, IEE Colloquium on; 07/1990

  The authors describe the production of an EMC CAD package for use in the design of electronic computing equipment. The design of electronic equipment is split up into several separate areas such asThe authors describe the production of an EMC CAD package for use in the design of electronic computing equipment. The design of electronic equipment is split up into several separate areas such as circuit design, circuit layout, enclosure design, and thermal design. EMC considerations are taken into account at all stages in the design process